Agricultural machine



June 6, 1.944. w. G. CHARLEY :TAL

AGRI CULTURAL MACHINE Filed Aug. 15, 1941 3 Sheets-Sheet 1 June 6, 1944.

W. G. CHARLEY ET AL AGRICULTURAL MACHINE 3 Sheets-Skiset 2 Filed Aug. l5. 1941 Mum.,

A w, ww D, .WQ 1.

w. G. CHARLEY ETAL .2,350,587

AGRICULTURAL MACHINE Filed Aug. 15, 1941 3 Sheets-Sheet 3 @wm/Mom y `ime 1944.

Patented June 6, 1944 AGRICULTURAL MACHINE Walter G. Charley, La Crescent, Minn., and August G. Buln', La Crosse, Wis., assignors to Allis-Chalmers Manufacturing Company, Milwaukee, Wis.. a corporation of Delaware Application August 15, 1941, Serial No. 407,032

16 Claims.

tical component of the draft force, which tends `to lift the tool out of the ground. The vertical component of the draft force is counteracted by the weight of the tool and its support which is movable up and down relative to the machine frame, and in the case of a cultivator or' other machine having a suction producing tool, or a pluralityof suction producing tools, the vertical component of the draft force is counteracted by the gravitational and suction forces acting upon the tool or implement unit.

As the machine advances with the tool or tools adjusted to a working position the tool` or tools encounter varying conditions of soil reaction, for instance by running into hard or soft spots in the ground or into local rises and hollows of the ground, and the draft force accordingly increases and decreases. A certain soll reaction, however, may be assumed to be prevalent as a normal Working condition.

It is an object of the invention to providev an improved machine of the mentioned character, `ln which the vertical component of the draft force, under normal working conditions, is overbalanced by the gravitational and suction forces acting upon an up and down adjustable tool or implement unit. The advantage to be accomplished by this provision is that no spring pressure is required to hold the tool or implement unit in its operating position under normal working conditions, and the improved machine, as contemplated by the invention, is further so constructed that the desired result is obtained without incorporating unusual weight in the tool or implement unit.

Another object of the invention is to provide an improved machine of the mentioned character in which the vertical component of the draft force is overbalanced by the' combined gravitational and suction forces under normal working conditions, and in which provisions are made to restrain the tool or implement unit from jumping out of the ground if the tools run into hard ground or into a rise of theground, and the vertical component of the draft force becomes strong enough to overbalance the gravitational and suction forces acting upon the tool or implement unit,

Another object of the invention is to provide a mechanism affording the mentioned restraint upon the tool or implement unit without reliance upon two-Way actuating mechanism for raising and lowering the tool or implement unit, so that a. simple and inexpensive one-way actuating mechanism may be used to raise the tool or implement unit from its operative to its inoperative position, and the tool or implement unit may be permitted to move into its operating position by its own weight, and under the action of the suction forces if suction producing tools are used.

These and other objects and advantages of the inventionV will be more fully apparent from the following description of a preferred embodiment of the invention shown in the accompanying drawings. Referring to the drawings in which like reference characters designate the same or similar parts in the various views:

Fig. 1 is a side view of a tractor and cultivator mounted thereon, showing the cultivator adjusted to an Aoperative-position, the near rear wheel of the tractor being omitted to expose rear connections of the cultivator with the tractor;

Fig. 2 is a top view of the machine shown in Fig. 1;

Fig. 3 is a rear view of the machine shown in Fig. 1;

Fig. 4 is an enlarged View of a detail of the cultivator shown in Figs. 1 to 3;

Fig. 5 is an enlarged section on line V-V of Fig. 1; and

Fig. 6 is a diagrammatic view of one of the front tool units of the cultivator shown in Fig. 1, together with its4 draft connections, the diagrammatic view illustrating the distribution of forces toy which the tool unit and draft connections are subjected during operation of the cultivator.

'I'he tractor shown in the drawings is a tricycle type tractor having widely spaced rear wheels l and 2 and a pair of closely spaced front wheels 3 and 4 centrally ahead of the rear wheels I and 2. An upwardly arched rear axle structure on which the rear wheels are mounted comprises a central gear casing 6 and side arms 'l and 8 having outer housing portions l' and 8' depending at the outer ends of the side arms and enclosing nal drive gears for the rear wheels l and 2. Secured to the gear casing 6 at the forward side ofthe rear axle structure is a torque tube casing 9, which hasan elongated relatively narrow portion extending longitudinally of the tractor and terminating at the forward end of the torque tube casing in a Irearwardly tapering bell housingr having mounting pads il at opposite sides of the tractor. An internal combustion engine I2 is rigidly secured to the torque tube casing 3, at the forward end of the bell hous. ing, and a bracket I3 secured to the forward end of the engine I'2 is supportingly connected with a pedestal I4.on which the front wheels 3 and 4 are mounted. An operators seat at the rear oi' the tractor comprises a seat cushion i8 `supl ported by longitudinal frame bars I1 and i8 secured intermediate their ends to the side arms 1 and 8 of the rear axle structure and connected together at their forward ends by a cross-bar i3 mounted on and extending transversely of the torque tube casing 9. The operators seat also includes a backrest 2i which is supported on the support for the seat cushion at a suitable distance above the seat cushion. .A steering wheel 22 within reach of an operator seated on l the cushion i3 is operatively connected with the front wheels 3 and 4 bv a steering mechanism including a reach rod 23 at the left side of the tractor. The reach rod is arranged in an ele vated position relative to the mounting pad ii at the left side of the tractor and relative to the bracket i3 so as to leave an unobstructed spacefor mounting an' implement attachmentl on the tractor below the reach rod.

Referring to Fig. 2, a square cross-bar 24 extends transversely of the tractor 'below the engine i2 and is rigidly secured to the bracket i3 by a pair of hangers 26,. the hangers being detachably secured to the bracket i3 bybolts 21. The crossbar 23 serves as a forward support for a, pair of draft frames 28 and 29 at opposite sides of the tractor. The draft frame 28 comprises a pair of square tubular draft bars 3l vand 32,'on`e rearwardly of and above the'other. and which 'are rigidly connected at their outer ends by a plate member '33 and at their inner ends by s. strap 84 which has a bent rearward extension boltedto the mounting pad il at the left side of the-trac... tor at $6. `Secured to the forward draft bar Si are an angle clip 31 and a U-clin 38, the-angle clip 31 having an upper ieg overlying the crossbar 26, and a boit 39 extends throughthe upper ieg of the clip 31 and is screwed' into a tanned hole at the outer end of the cross-bar 24 to rigidly secure the clip 31 to theI cross-bar 2S. The U- clip 38 is open at its forward end. and its legs are spaced to provide a close t on the cross-bar 24 at the top and bottom sides of the latter.

"I'he draft frame 29 at the right side of the tractor is constructed and arranged in the same manner as has just been described in connection with the draft frame 28, that is. the draft frame comprises a pair of scuare tubular draft bars 42, d3, as shown in Fig. 2, which correspond .to the draft bars 3| and 32, and which extend transversely of the tractor, one rearwardly of and above the other. An angle clipI 31' corresponding to the angle clip 31, and a U-clip 38', corresponding to the lU-clip 38, connect the draft frame 23 to the cross-bar '24 at the right side of the tractor, and a strap 34', corresponding to the strap 34, is bolted to the mounting pad l I at the right side of the tractor at 36. f

A pair of plate members 44, 48 extend between asados? the draft bars 3| and 32 of the draft frame 28, each plate member having a ilat rearward portion underlying the draft bar 32 and a fiat forward portion overlying. the draft bar 3|. A hole in the forward portion of the plate member 44 registers with one of a series of holes 41 in the draft bar 3l, and another hole in the rearward portion of the plate member n44 `registers with one of a series of holes 43 in the draft bar 32. The plate member 44 is secured to the draft bar 3| by a screw bolt 48 extending through the mentioned forward hole of the plate member and the registering hole in the draft bar 3l, and anotherV bolt 4i extends through the hole in the rearward portion of the plate member 44 and through the registering hole in'the draft bar 32 to secure the plate member 44 in xed position on the draft frame 28.

The second plate member 46 on the draft frame 28 is mounted in the same manner as ha's just been described in connection with the plate member 44, and a pair of bolts corresponding to the bolts 48 and 5i secure the plate member 4E to the draft bars 3l and 32.

Another pair 'of plate members 52, E53 are adiustably mounted on the draft frame 29 in the manner explained hereinbefore in connection with the plate members 44, 46 of the draft frame 28, the draft bars 42 and 43 having longitudinal series of holes 41 and 48', respectively.

Referring to Fig. 2, each of the plate members t8, d4, and 53, 52 has an oblong elevated portion 55 which is formed by pressing the plate members in a 'set of dies for the purpose of increasing the bending strength 'of the plate members. A bracket t is secured to the plate member 44, as shown in Fig. 1, in a depending position forwardly of the elevated rear end of the draft frame 28, preferably by welding. The bracket 54 is formed by bending a plate metal blank into U-shape, as

Yshown in Fig. 5, to provide a pair of side flanges to the bracket 54 between the forward and rearward dranl bars 3 i, 32, and each of the plate members 52, S3, also has a. depending bracket, corresponding to the bracket 54, between the draft Referring in Fig. l, a tool support comprises a rig .beam 56 and a bracket 51 secured to the forward cnd of the rig beam 56 in an upstanding position, preferably by welding. The bracket 51 is formed, like the bracket 54, by bending a, plate metal blank into U-shape to provide a pair of side anges which are spaced transversely of the tractor and connected bya web at the rear side of the bracket 51. l

Referring to Fig. 5, a pair ofhardened steel bushings 60 and 60' are mounted ina pair o f substantially alined holes in the side flanges of the bracket 54 atthe ylower end of the latter, the bushings having annular shoulders` bearing against the outer sides of the bracket and being securely held in place, preferably by fillet welds between the shoulders and side anges of the bracket. A lower draft link Si is mounted between the side flanges of the bracket 54 by means of a hardened steel pin 58 which is journaled in the bushings 60 and 60 and has a close running iii: therein. The link 8i is made from a blank of round bar stock by upsetting the ends of the blank -to form an eye `on each end of the link, the pin 58 being press-tted into the eye at the forward end ofthe linkhand the eye being of such thickness as to nt closely but freely between the relatively opposed end faces of the bushings `60 and 60'.

Another pairsof hardened steel bushings 65 and 65? are mounted in substantially alined holes of the side flanges, of the bracket 51 n'ear the lower end of the latter, the bushings 65 and 65' being exact duplicates of the bushings 60 and 60' and secured to the bracket 51 in the same manner as has been described hereinbefore in connection with the bushings 60 and 60'. A hardened steel pin 63 which is an exact duplicate of the pin 58 is journaled inthe bushings 65 and 65' and pressfitted into the eye at the rear end of the link 6I which closely but freely fits between the relatively opposed end faces of the bushings 65 and 65'.

An upper draft link 62 (Fig. l) connects the upper end of the bracket 51 with an upper portion of the depending lbracket 54 in the same manner as has been explained hereinbefore in connection with the lower draft link 6i. The upper draft link 62 is an exact duplicate of the draft link 6| and is mounted on the brackets 54 and 51 by pivot pins 59 and 64 which are exact duplicates of the pivot pins 58 and 63, the pins 59 and 64 being journaled in hardened steel bushings the same as the bushings 60, 60' and 65, 65'. The bracket 51 is thus connected with the bracket 54 for free up and down movement relative to .the latter.

A tool shank 66 is secured to the rig beam 56' by a clamping device 61 permitting vertical ad, justment of the tool shank 66 on the rig beam 56, and a cultivating. shovel 66 is mounted on the lower end of the tool shank 66 in the usual manner by an adjustable connection 69 permitting pivotal adustment of the cultivating shovel about a pivot center 1| to v'ary the suction of the cultivating shovel 88. 'Ihe shovel 68 is releasably held in its operative position on the tool shank 66 by a spring trip mechanism 12 of conventional construction.

Secured to the lower link 6| between the brackets 54 and 51 is an arm 13 which extends upwardly from the lower link and is offset towards the tractor to permit movement of the arm past the bracket 54 in a forward direction about the pivot center 58. The arm terminates at its upper end below the draft frame 28 at such a distance therefrom that it may clear the forward draft bar 3| when swung forwardly to raise the rig beam 56. f

Referring to Fig. 2, the rig beam 56 has a forward portion extending longitudinally of the tractor and a rearward portion at an angle relative to the forward portion, extending rearwardly and away from the tractor, the rearward portion affording a section for mounting another cultivating shovel (not shown) in laterally offset relation to the cultivating shovel 66. Another tool support comprising a rigl beam 14 is connected with the depending bracket of the `plate member 46 in the same manner as has been described hereinbefore in .connection with. the tool support 56, 51. The rig beam 14 is's'imilar to the rig beam 56, but angled in the opposite direction so that the rear portion of the rig beam 1.4 extends rearwardly towards the tractor. A cultivating shovel 16 is mounted on the forward portion of the rig beam 14 in the same manner as the cultivating shovel 66 is mounted on the rig beam 56, and the tool support carrying the shovel 16 may be raised and lowered in the same manner as the tool support carrying the shovel 66,

that is. by means of an arm 11 (Fig. 2) secured to the lower one of the parallel links which are pivoted on the depending .bracket of the plate,

member 46.

The spacing between the plate members 44,l 46 on the draft frame 26 is such as to permit the` shovels 66 and 16 to travel at opposite sides of a plant row extending longitudinally of the tractor, and the shovels 68 vand 16 may conveniently be adjusted to work closer to or farther away from such plant row by adjustment of the plate members 44, 46 on the draft frame 28.

Another pair of rig beams 16, 19 corresponding tothe rig beams 56 and 14 are arrangedat the other side of the tractor and connected with the depending brackets of the plate members 52 and 53, respectively, in the same manner as has been described hereinbefore in connection with the mounting of the rig beams 56 and 14 `on the draft frame 28. That is, the rig beams 18, 19 may be raised and lowered by fore and aft movement of arms 8|, 82 about lower pivot centers on the brackets depending from the plate mem-l bers 52 and 53.

Referring to the rear part of the 'cultivator which is mounted at the rear of the tractor, a stationary bracket .88 is secured to the left frame bar I1 by a pair of bolts 84, the bracket having a bearing boss 86 (Fig. 3) and extending upwardly beyond the bearing boss 86 to provide a pivot center at 81. Another stationary bracket 86, corresponding to the bracket 83, is secured to the frame bar I8 at the right side of the tractor and has a bearing boss 89 in alinement with the bearing boss 86 of the bracket 83. The bracket 88 extends upwardly beyond the bearing boss 69 to provide a pivot center at 9| (Fig. 3)- corresponding to the pivot center 81 on the bracket 93. Rotatably mounted in the bearing bosses 66, 89 is a rock shaft 92 which has a rock arm 93 on its outer end at the left side of the tractor, and a rock arm 94 at the right side of the tractor. Pivoted on the outer end of the arm 93 at 96 (Fig. 1) is a bent strap 91 and a link 96 extends between the lower end of the strap 91 and a bracket 69 on the tractor. The arm 93 and the link 98 cooperate to guide the strap 91 for up and down movement relative to the tractor.

The arm 84 at the right end of the rock shaft 92 extends in the same direction as the arm 93, and another strap I0| (Fig. 3), corresponding to the strap 91, is pivoted on the arm 94 at |02 and connected at its lower end with a bracket |03 on the tractor by a link |04 (Fig. 2) corresponding to the link 88. The straps 91 and |0I carry a transverse beam |06 which has a pair of gusset plates |01 welded thereto adjacent to the straps 91 and IOI,the gusset plates being rigidly secured, respectively. to the straps 81 and |0|. The transverse beam |06 carries a pair of track eradicating tools, |08, |09 behind the rear wheels I and 2, respectively, of the tractor, and a third track eradicating tool-III in position to loosen the soil on the track of the front wheels 3 and y4 of the tractor.

Figs. 1 and 3 show the track eradicating tools in an operative position, and a one-way actuating mechanism is provided for raising the track eradicating tools from their operative to .inoperative position. The one-way actuating mechanism comprises a hydrauliccylinder ||2 which is pivoted on a pin II3 (Fig. 2) welded to the lowerilange of the frame bar I8. A plunger ||4 cooperating with the hydraulic cylinder ||2 is pivotally connected at 6 to a pair of arms pivot center i|1 on the rock shaft 32. Secured to one of the arms ||1 (see Fig. 1) is a bracket |13 on which a crank screw |14 is adjvustably mounted, and the right frame bar I3 of the tractor hasL an abutment at its rear end which is engageable by the screw |14 in order to limit implement lowering movement of the rock shaft S2. The hydraulic cylinder ||2 is connected by a hose H8 with a pump mechanism ||3 mounted at the rear of the tractor and, operable by the engine |2, tached to a power take-oilhousing |20. enclosing suitable drive mechanism for the pump. A control mechanism, not shown, is incorporated in the pump mechanism, which permits, first, delivery of pressure fluid from the pump into the cylinder ||2 to cause rearward movement of the plunger ||4 relativevto the cylinder ||2, and.

consequent rotation ofthe rock shaft 92 in an anti-clockwise direction, as viewed in Fig. 1; second. to stop delivery of pressure fluid to the cylinder ||2 upon completion of the Power stroke of the plunger ||4. and at the same time to lock or entrap the pressure fluid in the cylinder ||2, which prevents return movement of the plunger from its extended position to the position in which it is shown in Fig. 1, and third, to release the pressure fluid which has been entrapped in the cylinder ||2 so that it may be discharged therefrom as further referred to hereinbelow. The control mechanism is also such to permit the pump mechanism to idle The pump mechanism ||8 is at- 'a pivotal connection with the arm 83 at a pivot center |34. Referring to Fig. 3. it will be seen that the second link |33 has a relatively long arm adjacent to the arm 33 of the rock shaft 92 and a shorter arm adjacent to a second arm |33 of the rock shaft 32,9. pin extending through the arms 33 and |33 of the rock shaft and through the arms of the second link |33, affording the pivotal connection |34. Another pin extending through both arms of the link |33 affords the pivot center |32 on' which the first link |3| is connected with the second link |33.

The outer arm of the second link |33 'extends beyond the pivot center |32, and a shoulder while the plunger H4 is in' the position of Figs.

92 in an anticlockwise direction position, and when the plunger ||4 reaches the end of its travel, thecontrol mechanism may be operated to stop delivery of pressure fluid into the cylinder so as to hold the transverse beam |06 in its elevated position.

The bracket 83 at the left side of the tractor has an upwardly extending portion affording a pivot center 31, as has been stated hereinbefore, and swingable on the pivot center 81 is a hand leverY comprising a handle bar |2| and a crossbe i 22 which is welded to the handle bar |2| and pivotedy to the bracket 83 at the pivot center 81. A latch |23 is pivoted on the free end of the cross bar |22, and a notched segment |24 engageable by the latch |23 is secured in a fixed position on the bearing boss 86 of the bracket 83. The latch |23 is held by a suitable spring (not shown) in engagement with the notched segment |24 and may be released manually by means of a grip lever |23 which is pivoted on the handle bar |2|, at |21, and connected with the latch |23 by a heavy wire |28. Pivoted on the rear end of the handle bar |2| at a pivot center |28 is a first link |3| which has a second pivot center |32 ata distance from the pivot center |28 equal to the spacing of the |29 from the pivotl center 31. Pivotally connected with the first link |3| at the pivot center |32 is a second link |33 which has |3|, as shown in Fig. 2.

pin |31. best shown in Fig. 4, is pivotally connected to the upper end of the second link |33 l by means of a pivot pin |33. A tubular rod |39 is telescopically slidable, at its rear end, on the shoulder pin |31. and welded tothe forward end of the tubular rod |33 is a nut 94|. An eye-bolt |42 is threaded into the nut |4| and pivotally connected at its eye with the upper endof the armi@ on the lower draft link 3| by means of a pivot pin |43. Referring again to the second link 33 'at the rear end of the cultivator, a rearwardly and upwardly extending bracket arm ist is :rigidly secured to the second link |33, and a coil spring 56 is hooked at one end into an eye at the upper end ofthe bracket arm itil. The other end of the spring |43 has a chain connection |41 with a lug |48' on the tubular rod |33.

Pivoted on the pin |33 is another shoulder pin |48 :(Fig. 2) corresponding to the shoulder pin |31, anda second tubular rod |3| is telescopically movable at its rear end on the shoulder pin |48. 'I'he second tubular rod |3| is connected at its forward "end with the arm 11 of the lower draft linkfor the rig beam 14 in the same manner as has been described in connection with the rod |38, that is, an eyebolt |52 is screwed into a nut at the forward end of the rod |3| and pivotally connected with the arm of the lower draftlink for the rig .beam 14. The forward end of the spring |46 has a chain connection |33 with a lug |34 on the rod The tool supports at tractor comprising the rig beams 1 3, 18 are operatively connected with the rock shaft 32 by a mechanism which is a duplicate of the mechanism at the left side of the tractor, which has been described hereinbefore, the mechanism at the right side, however, being arranged opposite hand relative to the mechanism at the left side, as may be seen from Figs. 2 and 3v. The mechanism at the right side of the tractor comprises a handle bar |33 'corresponding t'o the handle bar |2|, the handle bar |33 being swingable about the mentioned pivot center 9| on the bracket 83 at the right side of the tractorand operatively connected with the rock shaft 82 by a rstlink |31 and second link |38, corresponding to the first link |3| and second link |33. A pair Vof tubular rods |38, |3| are piv-l otally and slidably connected with the second link |33 at the right side of the tractor by means of shoulder pins |32, |33 corresponding to the shoulder pins |31 and |49. Effe-bolts |34, |36 adiustably connect the rods |39, |3| with the arms 8|, 82 of the lower 4draft links for the rig beams 13' and 18. A spring |31 is hooked, at its rear end, into a bracket |33 (Fig. 3) on the second link |33 at the right side of the tractor, and a pair of chains |39, |1| conthe right side of the l nect the spring |61 with lugs |12, rods |59, IBI, respectively. v Considering the operation of the mechanism which connects the rock shaft 92 with the forward implement units at the left side ofthe tractor, that is, with the outer implement unit comprising the rig beam 55, and with the inner implement unit comprising the rig beam 14, the following is to be noted. In the operative position of the front and-rear implement units, as shown in Fig. 1, the rear end of the tubular rod |39 abuts against the shoulder of the shoulder pin |31, the rear end of the tubular rod likewise abuts against the shoulder vof the shoulder pin |49, and the screw |14 bears upon the abutment on the frame bar vI8 ofthe tractor. The upper and lower draft links 6| and 62, of the outer unit extend rearwardly and downwardly from the bracket 54 at a relatively small angle relative to the horizontal, and when the tractor advances, the draft force acts upon the rig beaml 56 in the direction of the axis of the lower link 6| and may be considered as the resultant of a horizontal component and a |13 on the l vertical component, the latter exerting a lifting effect upon the rig beam 56, proportional to the draft force. This lifting effect of the vertical component of the draft force is counteracted by the weight of the outer implement unit connected with the rear ends off'the links 6|, 62 plus one half of the Weight of the links 6| and 62. The shovel 68, when drawn through the ground, develops a suction force which acts vertically in a downward direction and which, like the mentioned weight of the outer implement unit and one-half of the Weight of the links 6| and 62, counteracts. the lifting effect of the vertical component of the draft force. While the tractor advances, the soil resistance encountered by the shovel 68 may vary as the shovel runs into hard and soft spots of the ground and into local rises and hollows of the ground, with the result that the draft force alternately increases and decreases. A certain soil resistance, however, may be assumed to be prevalent as a normal working condition, and under said normal -working condition the combined gravitational and suction forces acting upon the outer implement unit overbalance the vertical .component of the draft force. This result is obtained without excessive weight of the implement unit and with ordinary suction of the shovel or shovelsA mounted on the rig beam 56 due to the relatively small angle of the links 6| and 62 relativeA to the horizontal.

Considering the tractor as a traveling support, the draft frame 28 and associated parts as draft means, and the rig beam 56 and associated parts as an implement unit including a suction producing ground engaging tool, it will be noted that the draft means include an element, namely the link 6|, transmitting draft from the traveling support to the implement unit in the normal operating position of the latter on' a forwardly and upwardly inclined line of draft at such an angle relative to the ground level that the vertical component of the draft force acting upon said implement unit under normal working conditions is overbalanced by the gravitational andsuction forces acting upon said implement unit iniits normal operating posi tion during advance movement of the machine.

Due to the superiority of the combined gravi# tational and suction forces over the vertical component of the draft force, under normal working s conditions, the arm 13 exertsya backward push upon the rod |39, which is transmitted to the shoulder pin |31, the rear end of the rod normally abutting 'against the shoulder pin as has been stated hereinbefore. Y V

The inner forward implement unit at the left side of the tractor, that is, the-onecomprising the rig beam 14, performs in the same manner as has been discussed hereinbefore in connection with the outer one comprising the rig beam 56. In other words, the' rod |5| is likewise subjected to a' rearward push uhder normal Working conditions, and such, rearward push acts upon the shoulder pin |49 which, like the shoulder pin |31, is pivoted on the second link |33 at |38. The combined rearwardly directed forces acting upon the pivot center |38 are transmitted, in part through the second link |33 to the rock armv 93,- so as to force the screw |14 against the abutment of the frame bar I8 of the tractor, and in part through the second link |33 to the first link |3| whichl transmits them to the hand lever |2|, |22. Since the hand lever is locked on the segment |24 the forces transmitted thereto through the link |3| are finally taken up on the bracket 83 at the pivot center 81 and at the bearing boss 86.

Assuming now that the shovels 68 and 16 run into a soft spot or a hollow which will cause a decrease of the draft force. Such a condition will have no effect upon the position of the shovels because it results merely in an increased rearward push upon the rods |39 and |5| due to a decrease of Athe vertical component of the draft force. which counteracts the combined gravitational and suction forces on the outer implement unit, and the increased rearward push on the rods |39 and |5| is taken up at the shoulder pins |39 and |49 which cannot move rearwardly from the position in which they are shown in Fig. l.

The result is entirely different, however, if the shovels 68 and 16 should runinto a hard spot or into a local rise of the ground. In that case the draft force increases and it may first be assumed for purposes of explanation that its vertical component becomes strong enough to balance the combined gravitational and suction forces of the inner and outer forward implement units at the left side of the tractor.r This will leave the rods |39 and |5| in the position in which they are shown in Figs. l and 2, but the rear ends of the rods |39 and |5I abut againstthe shoulders of the shoulder pins |31 and |49, the spring exerts a rearward pull upon the chains |41 and |53, the latter being adjusted to such length as to stretch the spring, and thereby provide an initial force resisting forward pull on the rods |39 and |5|.

Referring to Fig. 1, it will be noted that the mechanism which connects the outer front implement unit with the rock shaft 92 comprises two sections, namely a first one having fixed pivot centers at 58 and 92, and movable pivot centers at |43, |38, and |34.; and a second section having a xed pivot center at |29 and a movable pivot center at |32. The rod |39 and the shoulder pin |31 bearing normally'solid upon and bracketarm |46 may be considered as another reciprocable link of the first section, while the arm 13 and the arm 93 may be considered as a first and a second rock arm, respectively, ofthe tlrst section. The tensloned spring |66 reacts between the reciprocable links of the first section on a line overlying the pivot center |36, and the tension of the spring |66, therefore, tends to shift the rst section by angular displacement of the reciprocable link constituted by the link |33 and bracket arm |44 relative to the reciprocable link constituted by the rod |39 and the shoulder pin |31, but such tendency of the spring |46 remains substantially ineective, in the position of the tends in relatively close proximity to the pivot center |39. The link |3| opposes swinging movement of the reciprocable link |33, |46. about the pivot center |36 when the tension of the spring |46 is called upon to resist a forward pull on the rod |39. It, will be noted that t'ne link |3i, in the position of the parts shown in Fig. 1. occupies a toggle position relative to the reciprocable link constituted by the rod |39 and shoulder pin |31, and that the link |3| is subject to compression whena forward pull on the rod |39 is superimposed upon the tension of the spring |46 and, as a result, the forward pull on the `bracket |44 increases. Due to said toggle position of the link |3| the tendency of the link |3| to swing upwardly, under the mentioned conditions, about its pivot center |29l is very low, and the spring |46 may .be tensioned considerably in the toggle position of the link |3| shown in Fig. 1, before any appreciable lifting force is transmitted to the rear implement unit com'- prising Athe cross beam |06 and track eradicating tools |09, |09 and In other words the toggle positionof the link |3| relative to the reciprocable link |39, |31, or the toggle position of the reciprocable link |39, |31 relative to the link |3|, affords a relatively small lever ratio between the first swingabie link or rock arm 13 and the link |3|. On the other hand, it will be noted that in the toggle position of the recipJ rocable link |39, |31 relative to the link |36 the lever ratio between the second swingable link or rock arm 93 and the link |3| is relatively large.

The rod and shoulder pin |69 perform in the same manner asthe rod |39 and the shoulder pin |31, and what has been vsaid hereinbefore regarding the toggle position of the link |3| relative to the reciprocable link constituted by the rod |39 and shoulder pin |31 also applies to the rod |5| and shoulder pin |69.

As long as the rods |39 and |6| are subject to rearward push, as they are under normal working -conditions and when the draft force decreases,

the tension of the spring |66 supplements such rearward push but has no effect to hold the shovels 66 and 16 in the ground, soil penetration of the shovels being entirely dependent, under normal working conditions, on the gravitational and suction forces acting upon the respective tool units. However, if the shovels 68 and 16 i should run into hard ground, or into a local rise of the ground, the vertical component of the draft force may increase sumciently so that it will not only balance the gravitational and suction forces of the forward tool units but also exert a forward pull on the rods |39 and |5| greater than the initial tension of the spring |66. In

parts shown in Fig. 1, because the effective line of pull of the spring |66 exthat case the rods |39 and |6| will pull away yfrom the shoulders of the shoulder pins |31 and |69, and the shovels 69 and 16 will rise to a higher level. As a result, the shovels 66 and 16 will encounter less soil resistance. and a state of equilibrium will develop between the increased vertical component of the draft force, on the one hand, and the combined gravitational and suction forces plus the increased tension of the spring |66 on the other hand. In other words, if the shovels run into hard ground or into a local rise of the ground, the shovels will not Ijump out of the ground but stay in and merely ride at a somewhat different depth than under normal working conditions.

Referring to Fig. 6 which shows a diagrammatic view of the outer forward tool unit at the left side of the tractor together with its draft connections, 'the arrow W indicates the weight of the tool unit including the tool support 66, 61 and of the tool or tools mounted thereon plus one-half of the weight of the links 6| and 62. The arrow R indicates the soil reaction whose direction and magnitude vary according to soil conditions and according to the number and shape of the suction producing tools mounted on the rig beam 66. The arrow l indicates the pull on the lower link 6|, and the arrow u indicates the push on the upper link. The forces u and l aiect the tool support as one force F which acts axially of the lower link 6| and in the direction of the force l. The arrow C indicates an imaginary vertical force which would have to act upon the tool support 56. 61 in order to balance the force W plus the vertical component of R against the vertical component of F.

The direction and magnitude of the force C may easily be calculated for any given operating condition as follows. Assuming Wto be 40 pounds; R to be pounds; angle a to be 20 degrees, and angle to be 10 degrees, then a first condition to be met is that the sum of the forces in the direction of the line :v -x, designated as 2F: must be zero; that is:

it follows from Equation (1) that F pounds A second condition to be met is that the sum of the forces in the direction of the line u-u, designated as 2F., must be zero; that is;

(2) yEF|,=F (sin a) -i-C-W-R (sin =0 from` Equation (2) follows:

seen that if R increases to 220 pounds while the other assumed quantities remain unchanged, F increases to 231v pounds and C becomes zero, and if R becomes greater than 220 pounds. F increasesl accordingly and C becomes negative, which means that the shovel 63 tends to come out of the ground and that the rod |39 is subject to a certain pull in a forward direction. Such pull. as stated, will have to exceed the initial tension of the spring |46 before the rod |39 pulls away from the shoulder of the shoulder pin |31. l Referring to the lever comprising. the handl bar |2| and cross arm |22, it will be noted that adjustment of` this lever about its pivot axis at 81, in the position of the parts shown in Fig. 1, changes the operating depth of the cultivating shovels 68 and 16. Adjustment ofsaid lever in an upward direction is effective to swing the second reciprocable element constituted by the y link 33 and bracket arm |44 forwardly about the pivot center |34, with the result that therst reciprocable elements constituted by the rods 39, 5| and their respective shoulder pins |31 and |49 are moved forwardly and the shovels 68 and 16 are adjusted to a shallower depth than shown in Fig. 1. On the other hand, adjustment of the lever |2|, |22 in a downward direction from the position in which it `is shown in Fig. l,

moves the shovels 68 and 16 to a deeper operlittle by up and down adjustment of the depth y lever |2|, |22, and the action of the spring |46 is essentially the same as has been discussed hereinbefore irrespective of the position to which the depth lever |2|, |22 may happen to be adjusted. The mechanism at the right side of the tractor, which connects the rock shaft 92 with the implement units comprising the rig beams 18 and 19 operates in the same manner as the mechanism at the left side of the tractor, and what has been said hereinbefore regarding the operation of the mechanism at the left side of the tractor also applies to the mechanism at the right side of the tractor.

Admission of pressure iluid into the cylinder ||2 causes anti-clockwise rotation of the rock shaft 92, as viewed in Fig. 1, and consequently upward movement of the rock arm 93 from the position in which it is shown in said figure. The link |33, which is pivoted ony the arm 93 at |34 is guided on the tractor by the link |3| formovement relative thereto by movement of the arm 93, and when the arm 93 swings upwardly the linkage comprising the arms 13, 93 and the two reciprocable links |39, |31 and |33, |44 is shifted, with the result that the spacing of the effective line of pull of the spring |46 from the pivot center |38 increases.

more effective to assist the shifting o f the linkage initiated by upward movement of the rock arm 93. After a relatively short upwardvmovement ofjthe arm 93"fro'rn` the position in' which' it is shown in Fig. 1, the tension of the spring will materially assist the plunger ||4 to raise the rearward implement unit and the forward implement units at the left side of the tractor, lifting. force being transmitted to the forward implement units through the-rods |39 and |6|, the rod |5| performing in the same manner as has been discussed in connection with the rod |39.

The spring |46, therefore performs two functOnS. rSt. t0 hold the forward implement units in the ground when the tools run into hard ground and under similar adverse operating conditions, and second to facilitate the raising of the front and rear implement units. The latter function of the spring is of particular advantage, if instead of a power actuated mechanism, such as the hy- As the arm 93 swings upwardly4 the tension of the spring |46 becomes more and draulic cylinder 2 and plunger ||4, a manually operated lifting lever is employed.

It will be noted that the mechanism for raising and lowering the outer front implement unit at` the left side of the tractor comprises an actuating element, represented by the link |33. which is movable from a rst to a second position, and vice versa, and that means are provided to hold the actuating element in either of said positions, the link |3| and the crank screw |14 being effective to hold the actuating element in its rst position in which it is shown in Fig.,1, and the link l 3| and the hydraulic jack being effective to hold the actuating element in a second position when pressure fluid is admitted into and entrapped within the cylinder ||2. Considering the shoulder pin |31 as a thrust member pivoted to the actuating element |33, and the connection between the shoulder pin |31 and the outer front implement unit atthe left side of the tractor by means of the tubular rod |39 as a lost motion connection, it will further be noted that said lost motion connection permits upward movementl of the implement unit from its normal operating position while the actuating element is held in its rst position, and that` said lost motion connection is operable to raise the implement unit to an inoperative position by movement of the actuating element |33 from its iirst into its second position.v The spring 46 represents resilient means reacting between the actuating element and the implement unit to assist movement of the actuating element from said first to said second position, and the spring is effective. when the actuating element is held in its first position,-to supplement the mentioned gravitational and suction forces so as to urge said implement unit towards said operating position thereof upon increase of the draft force.

Referring to the plunger 4 as a reciprocable element, it will be further noted that said reciprocable element is movablejrom a first to a second position by fluid pressure created by the engine of the tractor, and that the raising and lowering mechanism for either 0f the front tool |39 may be referred to as a pair of actuating ele'y ments which are respectively connectedhvwith the tool support and withthe reciprocable element 4M, and it,will be vnoted thatone of said actuating elements has a lost motion connection with the other for the purposes stated hereinbefore.

The travel of the plunger ||4 is limitedso that at the end of the power stroke of the plunger the pivot center |32 coincides with the pivot center 81, the spacing between the pivot centers |29 and |32 being equal to the spacing between the pivot centers |29 and 81, as has been pointed out hereinbefore. As a result of this arrangement the depth lever |2|, |22 may be moved, in the raised position of the cultivator, about its pivot center at 81 to any position of adjustment along the segment |24 without causing movement of the link |33 and consequent up and down movement of the front implement units at lthe left side of the tractor. In other words, irrespective of the position to which the hand lever |2I, |22 has been ad.

' lar rods |5I,

,plement units 'bracket 8B on the tractor. The weight commined height above the ground, and the hand lever I2I, |22 may be adjusted to itsextreme lower 4or to its extreme upper position without affecting the kheight to which the forward impiement umts are raised above the ground by a full stroke of the plunger Ill. The mechanism which connects the rock shaft 32 with the front tools at the left side of the tractor therefore functions in 'the manner of a constant height lift mechanism.

and the mechanism which connects the rook shaft l 32 with the front tools at the right side of the tractor, vbeing an opposite hand duplicate of the lift mechanism at the left side of the tractor, also functions in the manner of a constant height lift mechanism. l A

In the inoperative or raised position of the cultivator, the weight of the implement unit connected with the bracket 54 tends to swing `the arm 13 in a rearward direction resulting yin a backward push upon the tubular rod |33, and the tubu- ISB, and .IBI are similarly subjected to a rearward push in the raised position of the implement due to the weight'of the forward imconnected with said rods. I'he rearward push acting upon the rods |33 and IBI in the raised position of the cultivator, due to the weight of the forward implement units at the left side of the tractor. is transmitted in part through the second link |33 to the rock arm 93, and in part through the second link |33, the first link I3I, handle bar I2I and cross-bar |22 to the pivot center 81 on the bracket 33 which is fixed on the tractor. Similarly, the rearward push acting upon the rods |59 and |6I in the raised position of the cultivator, due to the weight of the forward implement units at the right side of the tractor, is

transmitted in part through the second link |53 to the rock arm 93. and inkpart through the link |51,\.handle bar |56 and its cross-arm to the ponents of the forward implement units at the left and right sides of the tractor, 'which `are transmitted to the rock shaft 92 through the links |33 and |58 in the raised position of the- 5o 'cultivator tend to rotate the rock-shaft 92 in a clockwise direction as viewed in Fig. l, and the weight of the rearward implement unit comprisiing the transverse beam IM and track eradicat-y ing tools |08, |09, III also tends to rotate this rock shaft 92 in clockwise direction as viewed in l.

Fig. 1.

The weight of all forward implement units and the weight of the entire rear implement unit will therefore cooperate to, produce a torque upon the rock shaft 92 in a clockwise direction, as viewed 450 in Fig. 1, which torque will become effective .to rotate the rock shaft upon'release of the fluid which is entrapped in the cylinder Il! in order to hold the forward and rearward implement units in their inoperative position. The clockwise rotation of the rock shaft 32 will continue until the crank screw Ill which is mounted in the bracket |16 on one of the arms II1 of the rock shaft engages the fixed abutment on the right frame bar I8 on the tractor. The depth to which the track eradicating tools penetrate the ground may be adjusted by rotation of the crank screwv |14, while the normal depth to which the forward cultivating shovels penetrate the ground may be adjusted 7| asados? byv thedepth levers at opposite sides of the tractor. as has been explained hereinbefore.

' Clockwise rotation of the rock shaft l2 towards `the position in which it is shown in Fig. 1 will also restore-the mentioned initial tension of the springs I and |61, which has been reduced by upward movement of the rock arms 93 and I4.

and it will also push the plunger III back into the cylinder IIZ. which backward movement of mev plunger will transfer the fluid from the cylinder Il! through the hose III back into a sump within the power take-off housing |20.

`When the machine traverses a field with 'the tools lowered to operative position. a stone or otherobstruction may be encountered by one of the front shovels, and the corresponding rig beam may be forced upwardly from its normal operating position. Assuming that such action takes place on the rig beam DI, it will be seen that the rod |33 will be pulled forwardly, but such forward pull will not be transmitted to the adjacent rod |5I, since the chain |41 takes the whole pull, while the 'chain |53 relieves the rod IBI from the tension of the spring |46, but the rig beam14 will not rise "as long as the soil resistance-encountered by the shovel or shovels of the rig beam 'I3 remain normal in which case the gravitational and suction forces on the rig beam 14 overbalance the vertical component of the draft force transmitted to the rig beam 14 and the rod ISI is subject to a rearward push in spite of the slackening of the chain |53. The shovel or shovels on the rig beam 14 therefore will stay in the ground while the rig beam 55 is pushed upward from its normal position, by an unyielding obstruction.

For purposes of definition the rearward rock arm 93 may be considered as an actuating arm. and either of the forward rock arms 13 and 11 which are connected. respectively, with the outer and inner implement units at the left side of the tractor. may be considered as an implement lifting arm. The hydraulic Jack comprising the cylinder II2 and plunger III constitutes an actuating means for moving the actuating arm 93 from implement lowered to implementraised position, and either of the implement lifting arms 13, 11 is movable from implement lowered position in implementraising direction independently of the actuating arm. The mentioned lost motion connection between theshoulder pin |31 and the arm 13 by means of the tubular rod |39 is effective between the actuating arm 83 and the lifting arm `13, and functions to move the lifting arm 13 from said independent movement of the lifting arm 13 from its implement lowered towards its implement raised position while the actuating arm 93 isin its implement lowered position. The resilient Ameans represented by the spring |46 are operatively connected with the actuating arm 93 and with the implement lifting arm. 13 so as to assume a progressively strained condition by movement of the actuating arm 93 and lifting arm 13 to their implement lowered positions, and in said strained condition the spring I is effective to yieldingly restrain said independent movement of the lifting arm 13 and to assist in moving said lifting arm in implement raising direction upon movement of the actuating arm I3 from its implement lowered towards its implement raised position.

Considering the rod |33 as a reciprocable member pivoted to the first rock arm or implement lifting arm 13, it will be noted that the reciprocable member |39 is pivotally and slidably connected to the second link |33, and that the shoulder on pin |31 prevents sliding movement of the reciprocable member |39, by implement lowering movement of the arm 13., beyond la predetermined position relative to the link |33. The spring |46 biases the pivotal and slidable connection between the reciprocable member |39 and the link |33, and the spring is adapted to urge the reciprocable member |39 towards said predetermined position relative tothe link |33.

'I'he forward lifting arm 11 for the inner implement unit at the left side of the 'tractor is movable from an implement lowered position in implement raising direction independently of the forward lifting arm 13, and the lost motion connections between the shoulder pins |31 and |49 and the arms 13 and 11 by means of the rods |39 and |5| function as a lost motion device for moving both of said lifting arms from implement lowered position to implement raised position by a correspondingymovement of the actuating arm 93, and permitting each of the lifting arms 13, 11 to move from its implement. lowered position in implement raising direction independently of the actuating arm. 93. The spring |46 has one-way actuating connections, respectively, with the lifting arms 13 and 11 by means of the chains or flexible tension members I 41, |53, and a connection with the actuating arm 93 so as to assume a progressively strained condition by movement of the arms 13, 17 and 93 from their implement raised to their implement lowered positions, and in that strained condition the spring |46 is effective to yieldingly restrain the lifting arms 13, 11, severally and jointly, from movement in implement raising direction while the actuating arm 93 is in its implement lowered position, and to assist in moving the lifting arms 13, 11 in implement raising direction upon movement of the actuating arm 93 from its implement lowered towards its implement raised position.

While in the foregoing a preferred embodiment of the invention has been described with reference to the drawings, it should bev understood that it is not intended to limit the invention to the exact details of construction herein shown and described for various modifications within the scope of the appended claims may occur to persons skilled in art.

It is claimed and desired to secure by Letters Patent:

1. In an agricultural machine, a traveling support, an implement unit including a suction producing ground engaging tool, draft means connecting said implement unit with said support for up and down movement relative thereto and including an element transmitting draft from said support to said implement unit in the normal operating position of the latter on a forwardly and upwardly inclined line of draft at such an angle relative to the ground level that the vertical component of the draft force acting upon said implement unit under normal working conditions is overbalanced by the gravitational and suction forces acting upon said implement unit in its normal operating position during advance movement of the machine, and means for raising and lowering said implement unit comprising an actuating element movable from a ilrst to a second position and vice versa, means for holding said actuating element in either of said positions thereof, a thrust member pivoted on said actuating element and having a lost motion connection with said implement unit to permit upward movement of said implement unit from saidnormal operating position thereof while said actuating element is held in its rst position, and operable to raise said implement unit to an inoperative position by movement of said actuating element from its first into its second position, and resilient means connected to said actuating element independently of said thrust member, and reacting between 'said actuating element and said implement unit to assist movement of said actuating element from said first to said second position, said resilient means being effective, when said actuating element is held in said rst position, to supplement said gravitational and suction forces so as to' urge said implement unit towards said operating position thereof upon increase of said draft force. f

2. In combination with a tractor, a tool support, means connecting said tool support with said tractor for up and down movement relative thereto, a reciprocable element movable from a flrst to a second position by fluid pressure created by the engine of said tractor, and adapted to return from said second to said i'lrst position thereof upon release of said fluid pressure, and raising and lowering means for said tool support operatively connected so as to raise said tool support from an operative to an inoperative position by movement of said reciprocable element from said first to said second position thereof and so as to return said reciprocable element to said first position thereof by gravitational movement of said tool support from said inoperative to said operative position thereof, said raising and lowering means including a pair of actuating elements respectively connected with said tool support and with said reciprocable element, a thrust member pivoted on one of said actuatingA elements and having a lost motion connection with the other of said actuating elements to permit upward movement of said tool support from said operative position thereof while said reciprocable element occupies said first position, and resilient means connected to said one actuating element independently of said thrust member and reacting between said actuating elements to assist movement of said reciprocable element from said first to said second position and effective, when said reciprocable element is in said first position, to yieldingly resist upward movement of said tool support from'its 'operative position.

3. In combination with a tractor; a first implement unit including suction producing ground engaging tools, draft means connectingv said implement unit with said tractor for up and down movement relative thereto and including an element transmitting draft from said tractor to said implement unit in the normal operating position of the latter on a forwardly and upwardly inclined line of draft at such an angle relative to the ground level that the vertical component of the draft force acting upon said implement unit under normal working conditions is'overbalanced by the gravitational and suction forces acting upon said implement unit in its normal operating position during advance movement of the tractor, a reciprocable element movable from a rst to a second position by iiuid pressure created by the engine of said tractor, and adapted to return from said second to said first position thereof upon release of said fluid pressure, a, rock shaft mounted on said tractor and operatively connected with said reciprocable element to be rowith said reciprocable elementl tated by movement of the latter from its ilrst into its second position; a pair of actuating elements connected respectively with said rock shaft and with said implement unit, a lost motion connection between said actuating elements permitting upward movement of said implement unit from its normal operating position while said reciprocable element is in its ilrst position, and operable to raise said implement unit to an inoperative position by movement of said reciprocable element from its rst to its second position, resilient means biasing said lost motion connection and tending to raise said implement unit upon movement of said reciprocable element from its first towards its second position, said resilient means being effective to supplement said gravitational and suction forces so as to urge said implement unit towardsits operating position upon increase o! said draft force; a second implement unit mounted on said tractor for up and down movement relative thereto and operatively connected with said rock shaft so as to be raised from an operative to an inoperative position by movement of said reciprocable element from its first to its second position, and so as to hold said rock shaft by the weight of said second implement unit in said operative position of the latter against rotation in the direction in .which it is movable by said reciprocable element.

4. In an agricultural machine, a traveling support, a ilrst and a second rock arm swingable about relatively fixed pivotv centers, respectively, on said traveling support, a first link swingable about a third pivot center on said traveling support, a thrust transmitting connection between said rock arms comprising a second link pivoted to said second rock arm and pivotally connected to said first link, a reciprocable member pivoted to 4said first rock arm and connected with said second link for pivotal and limited sliding movement relative thereto to permit relative movement of said rock arms in one direction and limit relative movement of said rock arms in the opposite direction, and resilient means biasing said pivotal and slidable 'connection between said second link and said reciprocable member, adapted to yieldingly oppose said relative movement of said rock arms in said one direction, said thrust transmitting connection being operable by rocking movement of said second rock arm to swing said first link about its pivot center on said support into and out of a toggle position relative to said reciprocable member, affording a relatively small lever ratio between said rst rock arm and said rst link, and a relatively large lever ratio between said second rock arm and said first link, and rst and second implement units connected, respectively, with said first and second rock arms and tending, by their weight, to move said rst link and reciprocable member towards said toggle position relative to each other. t

5. In an agricultural machine, a traveling support, a first and a second rock arm swingable about relatively fixed pivot centers on said traveling support, a lever swingable about a third pivot center n said traveling support, releasable locking means for securing said lever in different positions of pivotal adjustment relative to said support, a lrst link pivoted on said lever, a second link pivotally connected with said first link and with said second rock arm, a pair of relatively reciprocable thrust transmitting elements connected, respectively, with said first rock arm and with said second link. stop means limitassess? ing relative movement of said thrust transmitting elements in one direction, resilient means resisting relative movement of said thrust transmitting elements in the opposite direction, whereby movement of said'second rock arm in one direction will be positively transmitted to said first rock arm, and said first rock arm may resiliently move in the same direction independently of said second rock arm, and first and second implement units connected, respectively, with said first and second rock arms and tending, by their weight, to move said rock arms in the opposite direction, said first link being freely swingable on said lever to permit lifting of said first and lsecond implement units by vswinging movement of said second rock arm independently of movement of said lever, and up and down adjustment of said first implement unit, independently of said second implement unit, by movement of said lever independently of movement of said second rock arm.

6. An implement adjusting mechanism for agricultural machines, comprising an. actuating arm movable from implement lowered to implement raised position, and vice versa, a lifting arm movable from implement lowered position in implement raising direction independently of said actuating arm, a lost motion connection between said arms for moving said lifting arm from implement lowered position to implement raised position by corresponding movement of said actuating arm and permitting said independent movement of said lifting arm, and resilient means operatively connected with said arms so as to assume a progressively strained condition by movement of said arms to their implement lowered positions, effective to yieldingly restrain said independent movement of said lifting arm and to assist in moving said lifting arm in implement raising directon upon movement of said actuating arm from its implement lowered to implement raised position. y

1, An implement adjusting mechanism for agricultural machines, comprising an actuating arm movable from implement lowered to implement raised position, and vice versa, a pair of implement lifting arms each movable from implement lowered position in implement raising direction independently of the other, a lost motion device connecting said actuating arm with said lifting arns for moving both of said lifting arms from implement lowered position to implement raised position by a corresponding movement of said actuating arm and permitting each of said lifting arms to move from its implement lowered position in implement raising direction independently of said actuating arm, and a single resilient element having one-way actuating connections, respectively, with said lifting arms and a connection with said actuating arm so as to assume a progressively strained condition by movement of all of said arms from their implement raised positions in implement lowering direction, effective to yieldingly restrain said lifting arms, severally and jointly, from said movement in limplement raising direction while said actuating arm is in its implement lowered position, and so as to assist in moving said lifting arms in implement raising direction upon movement of said actuating arm from its implement lowered to implement raised position.

\ 8. An implement adjusting mechanism for agricultural machines, comprising an actuating arm pivoted on the machine for movement from. implement lowered to implement raised position,

' said actuating arm, from implement lowered position in implement raising direction, a pail` of reciprocable members pivotally connected to said lifting arms, respectively, and each pivotally and slidably connected to said link, means for limiting sliding movement of said reciprocable members relative to said link whereby both of said lifting arms will be moved from implement lowered to implement raised position by a corresponding movement of said actuating arm, a tension spring connected at one end to said link,

and flexible tension members connectingl thel other end of said spring with said reciprocable members, respectively, said spring being progressively elongated by movement of all of said arms from their implement raised positions in implement lowering direction, and effective to assist in moving said lifting arms from their implementlowered to implement raised positions by said corresponding movement of said actuating arm. A

9. In an agricultural machine, a traveling support, an actuating arm pivoted on said support, a link pivoted on said actuating arm and guided on said support for movement relative thereto by movement of said actuating arm, an implement lifting arm pivotally movable on said support in implement raising and lowering directions independently of movement of said actuating arm, a reciprocable member pivotally connected to said lifting arm and pivotally and slidably connected to said link, means for preventing sliding movement of said reciprocable member, by implement lowering movement of said lifting arm, beyond a predetermined posiraising and lowering directions independently of movement of said actuating arm, a reciprocable member pivotally connected tov said lifting arm and pivotally and slidably connected to said second link, means for preventing sliding movement of said reciprocable member, by implementv lowering movement of said lifting arm, beyond a predetermined position relative to said second link, and resilient means reacting between said reciprocable member and said second link to urge said reciprocable member towards said predetermined position relative to said second link, said first link being freely swingable on said lever to permit movement of said lifting arm by pivotal movement of said actuating arm independently of movement of said lever, and by adjustment of said lever independently of pivotal movement of said actuating arm. I

l2. In an agricultural machine, a traveling support, an actuating arm pivoted on said support, a hand lever pivotally mounted on said ,support for adjustment to different positions, a

first-link having relatively spaced pivot centers,

tion relative to said link, and resilient means biasing said pivoted and slidable connection between said reciprocable member and said link, adapted to urge said reciprocable member towards said predetermined position relative to said link.

10. In an agricultural machine, a traveling support. an actuating arm pivoted on said support, a rst link pivoted on said support, a second link pivoted at relatively spaced points thereof to said actuating arm and rst link, an implement lifting arm pivotally movable on said support in implement raising andlowering directionsfindependently of movement of said actuating arm, a reciprocable member pivotally connected to said lifting arm and pivotally and slidably connected to said second link, means for preventing sliding movement of said reciprocable member, by implement lowering movement of said lifting arm, beyond a predetermined position relative to said second link, and resilient means biasing said pivotal and slidable connection between said reciprocable member and said second link, adapted to urge said reciprocable member towards said predetermined position relative to said second link.

l1. In an agricultural machine, a traveling supporhitlan actuating arm pivoted on said suppggigr-flever mounted on said support for adjustment, to different positions, a first link plvomesaid lever, a second link pivoted at relatively spaced points thereof to said actuating arm and first link, an implement lifting arm pivotally movable on said support in implement one fixed on said lever at a distance from the pivot axis thereof substantially equal to the spacing between said pivot centers, a second link connecting said actuating arm with the other pivot center of said first link, an implement lifting arm pivotally movable on said support in implement raising and lowering directions independently of movement of said actuating arm, a reciprocable member pivotally connected at one end to said lifting arm and pivotally and slidably connected at its other end to said second link, means for preventing sliding'movement of said reciprocable member, by implement lowering movement of said lifting arm, beyond a lpredetermined position relative to said second link, resilient means biasing said pivotal and slidable connection between said reciprocable member and said second link, adapted to urge said reciprocable member towards said predetermined position relative to said second link, and means connected with saidactuating arm operable to move the latter into vand out of a predetermined position in which the center of the pivotal connection between said ilrst and second links substantially coincides with the pivot axis of said hand lever, said resilient means being effective to assist movement of said actuating arm towards said predetermined position of the latter.

13. In an agricultural machine, a traveling support, an actuating arm pivoted on said support, a first implement unit connected with said actuating arm for movement thereby from a lowered to a raised position and tending, by its weight, to move said actuating arm towards` an implement lowered position, actuating means for moving said actuating arm from said implement l lowered to an implement raised position, a lifting arm pivoted on said support, a second implement unit connected with said lifting arm for movement thereby from a lowered to a raised position and tending, by its weight, to move said lifting arm towards an implement lowered position, means comprising a togglemechanism and a lost motion connection between said arms for moving both of said arms, by operation of said actuating means, from their implement lowered to implement raised positions, and permitting movement of said lifting arm from its implement lowered position towards its implement raised position independently of said actuating arm, and resilient means operatively connected with said arms so as to assume a progressively strained i condition by movement of said arms due to gravitational movement of said first and second'implement units from their raisedyt'o their lowered positions, said strained condition `of said resilient means being effective to assist said actuating means in raising said implements, and said toggle mechanism being effective to hold said actuating arm' in its implement lowered position against an increase of said strained condition of said resilient means due to said independent movement of said lifting arm.

14. In an agricultural machine, a tractor. a ground working implement. a draft connection betweensaid tractor and implement vertically swingable on said tractor and effective to exert a lifting force upon said implement proportional to the draft transmitted from said tractor to said implement through said connection, said implement and draft connection being constructed, mounted and arranged so that in normal operation of the machine. said lifting force will be insumcient to raise said implement from a predetermined ground working position but that said implement will tend to rise under the action of said lifting force when said .draft increases `in order to draw said implement through a hard spot or local rise of the ground; mechanism for raising and lowering said implement including an actuating element having a lost motion means connected with said actuating element and implement so as to assume a progressively strained condition by lowering movement of said implement and in said strained condition counteract said rising tendency of the latter.

l5. An implementv adjusting mechanism for agricultural machines, comprising an implement lifting arm and an actuating arm movable from implement lowered to implement raised positions, and vice versa, about relatively spaced pivot centers on the machine, a first reciprocable link pivotally connected with said lifting arm, a second reciprocable link pivotally connected with said first reciprocable link and swingably connected with said'actuating arm, a guide link having a pivot center on the machine and a pivotal connection with said second reciprocable link, whereby said implement lifting arm will be moved from its implement lowered to its implement raised position and said reciprocable links will I connection with said implement, and resilient be angularly displaced relative to each other in one direction by movement of said actuating arm from its implement lowered to its implement raised position, and resilient means connected to said reciprocable links at points thereof spaced substantial distances, respectively, from said pivotal connection between said reciprocable links, adapted to angularly displace said reciprocable links relative to each other in said one direction and thereby exert a force upon said arms tending to move the latter from their implement lowered to their implement raised positions.

16. An implement adjusting mechanism for agricultural machines, comprising an implement lifting arm and an actuating arm movable from implement lowered to implement raised positions, and vice versa, about relatively spaced pivot centers on the machine, a first reciprocable link pivotally connected with said lifting arm, a second reciprocable link pivotally connected with said first reciprocable link sind swingably connected with said actuating arm, a guide link having a pivot center on the machine and a pivotal connection with said second reciprocable link, whereby said implement lifting arm will be moved from 'its implement lowered to its implement raised position and said reciprocable links will be angularly displaced relative to each other in one direction by movement of said actuating arm from its implement lowered to its implement raised position, and resilient means connected to said reciprocable links at points thereof spaced 4substantial distances, respectively, from said pivotal connection between said reciprocable links. adapted to angularly displace said reciprocable links relative `to each other in said one direction and thereby exert a force yupon said arms tending to move the latter from their implement lowered to their implement raised positions, said pivot center of said guide link being so located on the machine that in the implement lowered position of said actuating arm said guide link will occupy a toggle position relative to said first reciprocable link, affording a relatively small lever ratio between said lifting arm and said guide link, and a relatively large lever ratio between said actuating arm and said guide link.

WALTER G. Canam. AUGUST G. Bunn. 

